This invention relates to optical correction, and in particular provides methods, devices, and systems for treating presbyopia and other vision conditions, for developing prescriptions for treatment of presbyopia and other vision conditions, and/or the like.
Presbyopia is a condition that affects the accommodation properties of the eye. As objects move closer to a young, properly functioning eye, ciliary muscle contraction and zonular relaxation may allow the lens of the eye to become rounder or more convex, and thus increase its optical power and ability to focus at near distances. Accommodation can allow the eye to focus and refocus between near and far objects.
Presbyopia normally develops as a person ages, and is associated with a natural progressive loss of accommodation. The presbyopic eye can lose the ability to rapidly and easily refocus on objects at varying distances. There may also be a loss in the ability to focus on objects at near distances. Although the condition progresses over the lifetime of an individual, the effects of presbyopia usually become noticeable after the age of 45 years. By the age of 65 years, the crystalline lens has often lost almost all elastic properties and has only limited ability to change shape.
To address the vision problems associated with presbyopia, reading glasses have traditionally been used by individuals to thus allow the eye to focus on near objects and maintain a clear image. This approach is similar to that of treating hyperopia, or farsightedness.
Presbyopia has also been treated with a number of alternative approaches. Many presbyopes are prescribed bi-focal eyeglasses, where one portion of the lens is corrected for distance vision and another portion of the lens is corrected for near vision. When peering down through the bifocals, the individual looks through the portion of the lens corrected for near vision. When viewing distant objects, the individual looks higher, through the portion of the bi-focals corrected for distance vision. Contact lenses and intra-ocular lenses (IOLs) have also been used to treat presbyopia, for example, by relying on monovision (where one eye is corrected for distance-vision, while the other eye is corrected for near-vision) or bilateral correction with either bi-focal or multi-focal lenses. In the field of refractive surgery, ablation profiles have been suggested to treat presbyopia, often with the goal of passively increasing the range of focus of the eye.
While the known and proposed methods for treatment of presbyopia have had varying degrees of success, none has proven to be ideal for all patients. In particular, generating prescriptions for extending the range of viewing distances without degrading the patient's vision (and satisfaction with their visual capabilities) can be challenging.
In light of the above, it would be desirable to have improved methods, devices, and systems for treatment of presbyopia. It would be generally desirable for these improved techniques to be compatible with known methods for treating refractive errors of the eye. Ideally, such improved eye treatment approaches might be relatively easy to implement without significantly increasing the complexity or cost for treatment of patients, while increasing the presbyopia treatment efficacy.